Nut and screw fastening



March 18,1941. J; MEISTERHANS 2,235,078

NUT AND SCREW FASTENING Filed Aug. 21, 1939 FIG-.1.

g X/////// I2 I Y ll INVENTOR.

JosEF MEIS TERM/INS.

HTTORNEY. W y

Patented Mar. 18, 1941 PATENT OFFICE NUT AND SCREW FASTENING Josef Meisterhans, Gotha, Germany. asslgnor to Gothaer Waggonfabrik Aktiengesellschaft,

Gotha, Germany, a company of Germany Application August 21, 1939, Serial No. 291,261 In Germany January 19, 1939 3 Claims. (01. 85-32) The invention relates to screw and nut fastenings of thelrind wherein the nut has flxed thereto a washer or flange by means of which it exerts the requisite clamping pressure when the screw is tightened up. Where the washer consists of metal and the part upon which the washer isv seated when the fastening has been made likewise consists of metal, a rigid or permanent connection between the washer and its seat can generally be made without diiiiculty, by means of screws or rivets, in order to give greater security, but this method is by no means easy where the part on which the washer rests is non-metallic, and'consists for example of the plywood frequent- 1y used in aircraft construction. Small screws fixingametalflangetoathinsheet ofplywoodgive a poor hold and are liable to cause considerable trouble.

According to my invention this is avoided by providing the nut with a non-metallic washer flxed thereto, and fastening this washer by means of adhesive to the part on which the nut rests when the fastening is made. This enables the nut to be flxed quite securely to the part which 25 it is to hold, with avoidance of all the inconvenience of drillingholes for screws or other measurea requiring a considerable degree of precision. Wherethepartwhichistocarrythe nutisa thick board or block the nut with its washer or flange may be counter-sunk in a cavity therein, the flange being fastened by means of the adhesive to a ledge within the cavity.

Anyconvenientmethodmaybeusedforflxingv them-metallic flange or washer tothe nut. A 35 preferredmethod available where the flange consists of moderately ductile material will be descrihedhereinafter.

Two i tsof theinvention areshownin thedrawing,inl"lgs.1and2re specfl'lellthefasteningshowninrimlbemg partlyinsectionandpartlyinelevation, and that showninl'igdbeinginelevatimwiththeparts heldbythenutandscrewinsection.

BeferringflrsttomJJisawasherofmouldedmateriaLmehastheplasticknownasm" andlisametalnuthavingatubularbossiengaging into the eye of the washer. The boss 3 is conically expanded, compressing the somewhat ductile material of the washer so as to lock the washer very securely to the nut. The screw l is screwed into the nut, which has at the top a cavity 5 with a flbre washer i therein.

In conjunction with the nut and the nonmetallic washer 2 the screw holds together a board 6 and a metal plate I and upon the under surface of the washer 2 there is a coating of adhesive I whereby the washer is permanently fastened to the board. For clearness the thickness of the adhesive coating is exaggerated in the drawing. On removal of the screw for separating the parts and 'I the washer I, holding the nut, remains flrmly attached to the part 6, ready for re-attachment of the part I. In the embodiment shown in Fig. 2 the nonmetallic part 9 to which the metal plate II is to be Joined has a cavity II. The insideportion of this cavity is of a diameter slightly larger than that of the nut II, but the outer part of the cavity is of sufllcient diameter to receive the non-metallic washer I3 and its depth is equal to the thickness of the washer. The coating M of adhesive is in this case on the upper face of the washer, which is by means of the adhesive attached to the ledge 'in the cavity ll.

What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. The combination, with a screw nut, of a washer of non-metallic material fixed to said nut and adapted to be fastened by means of adhesive to a non-metallic surface.

2. The combination of a screw nut having a central, coned annular boss, and a washer of nonmetallic material adapted to be fastened by means of adhesive to a non-metallic surface, said washer having a coned central bore and said boss engaging into said bore to lock said washer to said nut.

3. The combination, with a screw nut, of a nonmetaliic washer fixed to said nut and coated with adhesive on its lower surface for the purp s set forth.

JOBEF. 

